The invention relates to an apparatus for controlling a pressure in a fuel inflow line of a motor vehicle, having an inflow junction which is provided for connecting to the inflow line and having an outflow junction which is provided for returning fuel into a fuel container, and having a valve which is arranged in a connection between the inflow junction and the outflow junction.
In order to limit a pressure provided in an inflow line, pressure limiting valves have been disclosed which open above a predefined pressure and lead excess fuel back into the fuel container. The maximum pressure which is fed to the internal combustion engine is therefore limited.
In modern motor vehicles, however, there is the problem that fuel can emerge from an injection nozzle of the internal combustion engine after the internal combustion engine has been switched off. This fuel cannot flow back into the fuel container on account of a nonreturn valve which is arranged in the fuel container. In particular when the internal combustion engine is switched off in cold weather, the pressure in the inflow line rises as the temperature rises, and fuel emerges from the injection nozzle. Here, the pressure in the inflow line can rise from 0 bar to as much as 3 bar. In particular in future motor vehicles without pollutant emissions (what are known as zero emission vehicles), this can no longer be accepted.
The invention is based on the problem of designing an apparatus of the type mentioned in the introduction in such a way that it largely prevents fuel from emerging from the switched off internal combustion engine.